RICHMOND – While Terry McAuliffe and Ken Cuccinelli duke it out in the gubernatorial election, another race is being fought more quietly – one that could have a deciding effect on Virginia’s legislative system.

Democratic state Sen. Ralph Northam is facing Republican preacher E.W. Jackson for lieutenant governor. But GOP officials may be smiling even if Jackson loses, as polls predict. That’s because Northam would have to give up his seat in the now-evenly-divided Virginia Senate – opening the door for Republicans to capture an outright majority in that chamber.

Northam holds a 16 percentage-point lead over Jackson, according to the Roanoke College Poll. The survey, released Wednesday, showed Northam at 48 percent and Jackson at 32 percent. (The remaining respondents were uncertain or did not answer. The poll had a margin of error of 3.4 percentage points.) Previous surveys by The Washington Post/Abt SRBI and Christopher Newport University also gave Northam double-digit margins.

If Northam wins on Tuesday, a special election would be called to fill the seat representing the 6th Senate District, which includes parts of Norfolk and Virginia Beach and the Eastern Shore.

Norman Leahy, author of the politically conservative blog “Bearing Drift,” said the potential vacancy in the Senate is something neither party should take lightly.

“I would hope that both parties have been thinking about this for a long time. They would be fools not to,” Leahy said. “If a Republican were to win Northam’s seat, which I think is possible, it would drastically change the way the General Assembly works up until 2015, when the next Senate election is held.”

In Virginia, the lieutenant governor presides over the 40-member Senate and casts tie-breaking votes in that chamber. Bill Bolling, the current lieutenant governor, has been able to capitalize on that role because of the 20-20 party split in the Senate.

If a Republican wins Northam’s seat, the numbers would tilt 21-19 in favor of the Republicans.

“Republicans in the past have used Bolling to help organize the Senate and cast votes in their favor. If that seat is taken by a Republican, they would have an outright majority, and the lieutenant governor would be nothing more than a figurehead role,” Leahy said.

He said a shift in the balance of power could upset McAullife’s ability to govern if he were to win.

“If he [McAuliffe] wins and the Senate goes Republican, we would have a Democratic governor with an all-conservative legislative body. It would be very hard for Terry to get things done,” Leahy said.

Northam isn’t the only statewide candidate potentially vacating a Senate seat. Both candidates for attorney general – Democrat Mark Herring and Republican Mark Obenshain – are state senators.

VCU political science professor John Aughenbaugh predicted there will be two Senate seats vacated.

“I think McAuliffe is going to win the governor’s race, Northam lieutenant governor and Obenshain attorney general. That would mean special elections would be held for both Northam and Obenshain,” Aughenbaugh said.

Obenshain has a slight lead in most polls, although the Roanoke College Poll put Herring ahead. If Obenshain wins and must vacate his Senate seat, it wouldn’t have dramatic political ramifications, Leahy said.

“Obenshain represents an area that is pretty conservative. I highly doubt that a Democrat would have the opportunity to win that seat,” he said.

When a Senate or House seat becomes vacant, the governor calls a special election. Leahy said those campaigns can pose a challenge for political parties and candidates.

“These elections happen in a very compressed amount of time. They take place during an absolutely terrible time for a political race – right around the holiday season,” Leahy said. “Running that race is going to be tough for either party, but I know the Republicans are going to put everything they’ve got into winning if Jackson loses.”

The 6th District seat that Northam holds has voted both Republican and Democratic. From 1941 to 2000, the seat was held by a Democrat. But from 2000 to 2008, Republican Nick Rerras represented the district.

While Leahy believes the seat is up for grabs by either party, Democratic Delegate Algie Howell disagreed. Howell has been a delegate since 2004, representing some of the same parts of Norfolk and Virginia Beach as Northam. He doubts a Republican will take the seat.

“Anything is a possibility; it depends on who runs and how strong the candidate is. The district he [Northam] is in leans Democrat, so I don’t see a chances of Republican winning as that great,” Howell said.

Sen. Chap Petersen, D-Fairfax, also said he is optimistic a Democrat would win Northam’s seat.

“His district is a good Democratic district. I know at least two great candidates for that seat – Lynwood Lewis and Paula Miller,” Petersen said.

Sen. George Barker, D-Alexandria, also said he is confident in the Democrats’ chances to retain the 6th Senate District seat.

“I don’t think Ralph would have ran for lieutenant governor if he thought there was a strong chance a Republican would take his seat,” Barker said.

What makes the lieutenant gubernatorial race so interesting, Leahy said, is Jackson’s rise to the position. He has never held elective office and came out of nowhere to win the Republican nomination over six other candidates at the party convention on May 18.

“At the convention, Jackson’s people showed up, and they stayed through all of the ballots and won. I don’t think anyone was as surprised as him when he won the nomination,” Leahy said.

“Now he has to run a campaign he has never run before. His only prior experience was getting just over 4 percent of the votes in the U.S. Senate race. He’s like the dog who caught the car. Now, what’s next?”

Before his nomination, Jackson was relatively unknown, but he has made a name for himself with comments like “The idea Obama is a Christian is laughable.”

So how did Jackson win the nomination? Was it because of dedicated supporters, or was there something going on behind the scenes? Leahy said he believes ulterior motives could have factored into the nomination.

“I don’t think he was set up on purpose to lose to Northam to open up his Senate seat. I doubt the Republicans are that smart,” Leahy said. “What I do think could have happened was the other candidates were spiteful that Jackson won the early rounds of the convention and threw him their support with the mindset ‘If I can’t have this seat, no one can.’ “

Ultimately, Leahy said it is hard to predict anything when it comes to special elections. Past voting patterns and the specific district can only tell so much.

“If you look at history, some trends seem to be true. They work until they stop working. With a Democrat in the White House, Virginians assume the next governor will be a Republican, but it may not happen,” Leahy said.

“It all comes down a party’s ability to get people out in a low-turnout election. It puts both parties to a test stand. A candidate stands as good a chance as anybody in those elections.”